fix: Broken TypeScript declarations

package.json

@@ -29,85 +29,85 @@
     "exports": {
         "./core": {
             "import": {
-                "types": "./dist/esm/core.d.mts",
+                "types": "./dist/esm/core.d.ts",
                 "default": "./dist/esm/core.mjs"
             },
             "require": {
-                "types": "./dist/cjs/core.d.cts",
+                "types": "./dist/cjs/core.d.ts",
                 "default": "./dist/cjs/core.cjs"
             }
         },
         "./rollup": {
             "import": {
-                "types": "./dist/esm/rollup.d.mts",
+                "types": "./dist/esm/rollup.d.ts",
                 "default": "./dist/esm/rollup.mjs"
             },
             "require": {
-                "types": "./dist/cjs/rollup.d.cts",
+                "types": "./dist/cjs/rollup.d.ts",
                 "default": "./dist/cjs/rollup.cjs"
             }
         },
         "./webpack": {
             "import": {
-                "types": "./dist/esm/webpack.d.mts",
+                "types": "./dist/esm/webpack.d.ts",
                 "default": "./dist/esm/webpack.mjs"
             },
             "require": {
-                "types": "./dist/cjs/webpack.d.cts",
+                "types": "./dist/cjs/webpack.d.ts",
                 "default": "./dist/cjs/webpack.cjs"
             }
         },
         "./vite": {
             "import": {
-                "types": "./dist/esm/vite.d.mts",
+                "types": "./dist/esm/vite.d.ts",
                 "default": "./dist/esm/vite.mjs"
             },
             "require": {
-                "types": "./dist/cjs/vite.d.cts",
+                "types": "./dist/cjs/vite.d.ts",
                 "default": "./dist/cjs/vite.cjs"
             }
         },
         "./esbuild": {
             "import": {
-                "types": "./dist/esm/esbuild.d.mts",
+                "types": "./dist/esm/esbuild.d.ts",
                 "default": "./dist/esm/esbuild.mjs"
             },
             "require": {
-                "types": "./dist/cjs/esbuild.d.cts",
+                "types": "./dist/cjs/esbuild.d.ts",
                 "default": "./dist/cjs/esbuild.cjs"
             }
         },
         "./bun": {
-            "types": "./dist/esm/bun.d.mts",
+            "types": "./dist/esm/bun.d.ts",
             "default": "./dist/esm/bun.mjs"
         },
         "./webpack-loader": {
-            "types": "./dist/cjs/webpack-loader.d.cts",
+            "types": "./dist/cjs/webpack-loader.d.ts",
             "default": "./dist/cjs/webpack-loader.cjs"
         }
     },
     "typesVersions": {
         "*": {
             "core": [
-                "./dist/types/core.d.ts"
+                "./dist/esm/core.d.ts"
             ],
             "rollup": [
-                "./dist/types/rollup.d.ts"
+                "./dist/esm/rollup.d.ts"
             ],
             "webpack": [
-                "./dist/types/webpack.d.ts"
+                "./dist/esm/webpack.d.ts"
             ],
             "vite": [
-                "./dist/types/vite.d.ts"
+                "./dist/esm/vite.d.ts"
             ],
             "esbuild": [
-                "./dist/types/esbuild.d.ts"
+                "./dist/esm/esbuild.d.ts"
             ],
             "bun": [
-                "./dist/types/bun.d.ts"
+                "./dist/esm/bun.d.ts"
             ],
             "webpack-loader": [
-                "./dist/types/webpack-loader.d.ts"
+                "./dist/esm/webpack-loader.d.ts"
             ]
         }
     },
@@ -120,18 +120,17 @@
     "dependencies": {
         "@apm-js-collab/code-transformer": "^0.18.0",
         "es-module-lexer": "^2.1.0",
-        "module-details-from-path": "^1.0.4",
-        "magic-string": "^0.30.21"
+        "magic-string": "^0.30.21",
+        "module-details-from-path": "^1.0.4"
     },
     "devDependencies": {
-        "@types/node": "^20.10.4",
-        "meriyah": "^6.1.4",
         "@types/bun": "^1.3.14",
+        "@types/node": "^20.10.4",
         "esbuild": "^0.28.1",
+        "meriyah": "^6.1.4",
         "rollup": "^4.62.0",
         "tslib": "^2.6.2",
         "typescript": "^6.0.3",
-        "unplugin-dts": "^1.0.1",
         "vite": "^8.0.16",
         "vitest": "^4.1.9",
         "webpack": "^5.107.2"

src/bun.ts

@@ -3,7 +3,7 @@ import {
     createCodeTransformer,
     isJsFile,
     type CodeTransformerPluginOptions,
-} from './core';
+} from './core.js';
 import type { Plugin } from 'esbuild';
 
 /**
@@ -117,4 +117,4 @@ export default function codeTransformerBun(
     };
 }
 
-export type { CodeTransformerPluginOptions } from './core';
+export type { CodeTransformerPluginOptions } from './core.js';

src/core.ts

@@ -257,9 +257,9 @@ export type { CustomTransform, InstrumentationConfig, ModuleMatcher, FunctionBeh
 // Keep type and value exports in separate statements: inline `type` modifiers
 // in a mixed export emit TS 4.5+ syntax into the declarations, which breaks
 // consumers type-checking with older TypeScript.
-export { serializeInstrumentations, deserializeInstrumentations } from './instrumentation-serde';
+export { serializeInstrumentations, deserializeInstrumentations } from './instrumentation-serde.js';
 export type {
     SerializedRegExp,
     SerializableInstrumentationConfig,
     AnyInstrumentationConfig,
-} from './instrumentation-serde';
+} from './instrumentation-serde.js';

src/esbuild.ts

@@ -5,7 +5,7 @@ import {
     createCodeTransformer,
     isJsFile,
     type CodeTransformerPluginOptions,
-} from './core';
+} from './core.js';
 
 const filter = /\.(cjs|mjs|cts|mts|tsx|jsx|ts|js)$/;
 
@@ -170,4 +170,4 @@ export default function codeTransformerEsbuild(
     };
 }
 
-export type { CodeTransformerPluginOptions } from './core';
+export type { CodeTransformerPluginOptions } from './core.js';

src/rollup.ts

@@ -5,7 +5,7 @@ import {
   isJsFile,
   shouldSkipCodeInjection,
   type CodeTransformerPluginOptions,
-} from "./core";
+} from "./core.js";
 import MagicString, { SourceMap } from "magic-string";
 
 export default function codeTransformerRollup(
@@ -124,4 +124,4 @@ export default function codeTransformerRollup(
   };
 }
 
-export type { CodeTransformerPluginOptions } from "./core";
+export type { CodeTransformerPluginOptions } from "./core.js";

src/vite.ts

@@ -1,6 +1,6 @@
 import type { Plugin } from 'vite';
-import type { CodeTransformerPluginOptions } from './core';
-import codeTransformerRollup from './rollup'; // Ensure rollup types are included for TransformResult
+import type { CodeTransformerPluginOptions } from './core.js';
+import codeTransformerRollup from './rollup.js'; // Ensure rollup types are included for TransformResult
 
 export default function codeTransformerVite(
     options: CodeTransformerPluginOptions,
@@ -11,4 +11,4 @@ export default function codeTransformerVite(
     };
 }
 
-export type { CodeTransformerPluginOptions } from './core';
+export type { CodeTransformerPluginOptions } from './core.js';

src/webpack-loader.ts

@@ -6,7 +6,7 @@ import {
     deserializeInstrumentations,
     serializeInstrumentations,
     type AnyInstrumentationConfig,
-} from './instrumentation-serde';
+} from './instrumentation-serde.js';
 
 // Handle CJS default export - module-details-from-path exports a function directly
 const moduleDetailsFromPath = (moduleDetailsFromPathImport as any).default || moduleDetailsFromPathImport as any;

src/webpack.ts

@@ -3,8 +3,8 @@ import { fileURLToPath } from 'url';
 import { dirname, resolve } from 'path';
 import {
     type CodeTransformerPluginOptions,
-} from './core';
-import { serializeInstrumentations } from './instrumentation-serde';
+} from './core.js';
+import { serializeInstrumentations } from './instrumentation-serde.js';
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 
@@ -121,4 +121,4 @@ export default function codeTransformerWebpack(
     return new CodeTransformerWebpackPlugin(options);
 }
 
-export type { CodeTransformerPluginOptions } from './core';
+export type { CodeTransformerPluginOptions } from './core.js';

test/type-resolution.test.ts

@@ -0,0 +1,141 @@
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import {
+    mkdtempSync,
+    mkdirSync,
+    writeFileSync,
+    symlinkSync,
+    unlinkSync,
+    rmSync,
+    existsSync,
+} from 'fs';
+import { join, dirname } from 'path';
+import { spawnSync } from 'child_process';
+import { fileURLToPath } from 'url';
+import { createRequire } from 'module';
+
+// Regression tests for https://github.com/apm-js-collab/code-transformer-bundler-plugins/issues/40
+//
+// The published declarations must reference their sibling modules with explicit
+// extensions, otherwise they fail to resolve under TypeScript's Node16/NodeNext
+// module resolution with `error TS2307: Cannot find module` (or `TS2834`).
+// These tests type-check a consumer that imports every advertised subpath under
+// each resolution mode.
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const root = join(__dirname, '..');
+const tsc = createRequire(import.meta.url).resolve('typescript/bin/tsc');
+
+const PKG = '@apm-js-collab/code-transformer-bundler-plugins';
+const ALL_SUBPATHS = ['core', 'rollup', 'webpack', 'vite', 'esbuild', 'bun', 'webpack-loader'] as const;
+
+// `vite` ships `exports`-only type declarations that legacy `node10` resolution
+// cannot follow, so the `/vite` subpath's peer types are unresolvable there —
+// a limitation of vite itself, not of our declarations (which resolve fine).
+const NODE10_SUBPATHS = ALL_SUBPATHS.filter((s) => s !== 'vite');
+
+// A consumer module that imports (and references) each subpath, so an
+// unresolved declaration surfaces as a hard error rather than being elided.
+function consumerFor(subpaths: readonly string[]): string {
+    return (
+        subpaths.map((s, i) => `import * as m${i} from '${PKG}/${s}';`).join('\n') +
+        `\nexport const used = [${subpaths.map((_, i) => `m${i}`).join(', ')}];\n`
+    );
+}
+
+// `skipLibCheck: false` is essential: issue #40's TS2307 originates inside the
+// package's own declaration files, which `skipLibCheck: true` would hide.
+const baseCompilerOptions = {
+    target: 'esnext',
+    strict: true,
+    skipLibCheck: false,
+    esModuleInterop: true,
+    types: ['node'],
+    noEmit: true,
+};
+
+const modes = [
+    // Node16/NodeNext — the resolution that broke in #40. `.mts` exercises the
+    // `import` condition; `.cts` exercises `require`.
+    {
+        name: 'nodenext',
+        compilerOptions: { ...baseCompilerOptions, module: 'nodenext' },
+        files: ['consumer.mts', 'consumer.cts'],
+        subpaths: ALL_SUBPATHS,
+    },
+    {
+        name: 'bundler',
+        compilerOptions: { ...baseCompilerOptions, module: 'esnext', moduleResolution: 'bundler' },
+        files: ['consumer.ts'],
+        subpaths: ALL_SUBPATHS,
+    },
+    // Legacy resolution routes subpaths through `typesVersions` → the `.d.ts`
+    // files. `ignoreDeprecations` silences TS6's non-fatal `node10` deprecation
+    // warning so the mode actually runs; TS7 removes `node10` outright, which
+    // the skip below detects.
+    {
+        name: 'node10',
+        compilerOptions: {
+            ...baseCompilerOptions,
+            module: 'commonjs',
+            moduleResolution: 'node10',
+            ignoreDeprecations: '6.0',
+        },
+        files: ['consumer.ts'],
+        subpaths: NODE10_SUBPATHS,
+    },
+];
+
+let fixture: string;
+let symlink: string;
+
+beforeAll(() => {
+    expect(
+        existsSync(join(root, 'dist/esm/core.d.ts')),
+        'Declarations are missing — run `yarn build` before the tests.',
+    ).toBe(true);
+
+    // The fixture lives under the repo's own node_modules so that `@types/node`
+    // and `@apm-js-collab/code-transformer` resolve up the tree, exactly as
+    // they would for a real installed consumer.
+    fixture = mkdtempSync(join(root, 'node_modules', '.type-resolution-'));
+
+    // Symlink the package into place so resolution flows through package.json
+    // `exports` / `typesVersions` rather than a `paths` alias — that routing is
+    // precisely what we are testing.
+    const scope = join(fixture, 'node_modules', '@apm-js-collab');
+    mkdirSync(scope, { recursive: true });
+    symlink = join(scope, 'code-transformer-bundler-plugins');
+    symlinkSync(root, symlink, process.platform === 'win32' ? 'junction' : 'dir');
+});
+
+afterAll(() => {
+    // Unlink the symlink explicitly first so cleanup can never recurse into the
+    // repo it points at.
+    if (symlink && existsSync(symlink)) unlinkSync(symlink);
+    if (fixture) rmSync(fixture, { recursive: true, force: true });
+});
+
+describe('published type declarations resolve for consumers', () => {
+    it.each(modes)('$name: every subpath type-checks cleanly', (mode) => {
+        const source = consumerFor(mode.subpaths);
+        for (const file of mode.files) writeFileSync(join(fixture, file), source);
+
+        const tsconfig = join(fixture, `tsconfig.${mode.name}.json`);
+        writeFileSync(
+            tsconfig,
+            JSON.stringify({ compilerOptions: mode.compilerOptions, files: mode.files }, null, 2),
+        );
+
+        const { status, stdout, stderr } = spawnSync(process.execPath, [tsc, '-p', tsconfig], {
+            cwd: fixture,
+            encoding: 'utf8',
+        });
+        const output = stdout + stderr;
+
+        // `node10` was removed as a `moduleResolution` value in TypeScript 7;
+        // skip the mode if the installed compiler no longer accepts it.
+        if (/error TS510[78]|moduleResolution.*removed/.test(output)) return;
+
+        expect(status, output).toBe(0);
+    });
+});